E-Mail
DURHAM, N.C. - Decades after federal bans ended widespread use of lead in paint and gasoline, some urban soils still contain levels of the highly toxic metal that exceed federal safety guidelines for children, a Duke University study finds.
To conduct their study, the researchers analyzed and mapped soil lead concentrations along 25 miles of streets in Durham, N.C., a city of about 270,000 people. They found that while soil lead levels have generally decreased since the 1970s, they have decreased much less near residential foundations than along streets.
The researchers collected soil samples near foundations of houses built before 1978. Samples within a meter of the older homes averaged 649 milligrams (mg) of lead per kilogram (kg) of soil, more than three times the average level detected near streets, which was 150 mg/kg.